In recent years, as interest in health grows, the interest in aerobic endurance exercises such as marathon, jogging, cycling, and so on has grown. On the other hand, in the stressful society of modern age, it is also true that, many people are unable to find enough time to exercise due to long working hours and so on, lack of energy to exercise due to exhaustion from day-to-day overwork, or are unsuccessful in continuing to exercise even if they try. Moreover, every year, more school children are losing endurance as more of them become obese, which has become a serious social problem. For this reason, a method to enhance endurance easily, safely and effectively is strongly desired.
Understanding the above background, the development of food ingredients that enhance durability is underway. For instance, proanthocyanidin and lycopene (JP 2003-334022 A), an extract of crataegus cuneata (JP H8-47381 A), and so on, cacaonib (JP 2006-282576 A), catechin (JP 2005-89384 A), olive oil (JP 2009-161459 A) and the like have been reported as ingredients that enhance durability.
Alanylglutamine is a dipeptide comprising two amino acids called alanine and glutamine (“Clinical Science,” 1988, Vol. 75, No. 5, p. 438-8; “L-Alanyl-L-Glutamine,” Kyowa Hakko Kogyo, 2006, p. 1; WO2007/108530).